do you guys help newbies??

[Dennis Lee Bieber]

malik m fed this fish to the penguins on Wednesday 27 November 2002 
03:48 am:


> #chapter 3 test control structures 3.3
> print "hello, this program will tell me how many miles per gallon your
> car drives by the \n amount of miles entered by the user along with
> the size of his/her tank."
>
        You probably weren't expecting an English lesson either, but that 
intro is running "... me ... your ... the user ... his/her ..."; 
implies three different people are involved <G>

        You are also assuming that one always runs the tank empty before 
filling it, rather than using the amount of fuel needed to refill the 
tank.
 
> #initialize variables
> totalMilesDriven = 0 #total miles driven
> 
> totalGallonsPerTank = 0 #total gallons per tank
> 
> counter = 0 #bogus counter
> 
        Definitely bogus, if the only use is to see if the user entered real 
values you could just see if the totals are > 0.

> 
> while gallonsPerTank or milesDriven != -1:

        That is equal to

                (gallonsPerTank) or (milesDriven != -1)

Comparisons don't distribute so it is NOT

                (gallonsPerTank != 1) or (milesDriven !=1)

which is still incorrect, since someone could enter -1 for ONE item, 
but the other could be a positive number, and would make the statement 
true.

>     gallonsPerTank = raw_input("Enter how many gallons your tank
> holds, -1 to end:")
>     milesDriven = raw_input("enter how many miles driven, -1 to end:")
>
        Forgot to convert from string to numeric.
 
> #termination phase
> if counter != 0:


        This looks like a homework assignment, and I'm probably going to 
violate conventions (don't do their homework). Of course, by the time 
my message shows up, you'll have seen all the line-by-line critiques.

,----[ /home/wulfraed/t.py ]
| import string       # probably not needed in the newest versions of 
Python
|                     # strings have methods so just variable.upper()
|                     # could replace string.upper(variable)
|                     
| #chapter 3 test control structures 3.3
| #   as recreated by dlbieber/nov 20 2002
| 
| intro = """
| Hello. This program will tell you how many miles per gallon your
| car produces by dividing the amount of miles entered by the
| amount of fuel needed to refill the tank. The tank has to
| be full at the start of the trip!
| """
| 
| # initialize stuff
| sumMiles = 0.0
| sumGallons = 0.0
| 
| def ProcessSegment():
|     global sumMiles         #declare the running totals as external to
|     global sumGallons       #the function
| 
|     EOI = 0                 #initialize End Of Input to false
| 
|     userin = raw_input("Enter the miles driven in this segment (Q to 
end)  ")
|     if string.upper(userin) != "Q":
|         miles = float(userin)   # note: no check for invalid input is
|         made
|         userin = raw_input("Enter the numbers of gallons needed to 
refill (Q to end)  ")
|         if string.upper(userin) != "Q":
|             gallons = float(userin) # note: no check for invalid input
|             print "Miles per gallon for this segment: %s" % (miles / 
gallons)
|             sumMiles = sumMiles + miles
|             sumGallons = sumGallons + gallons
|         else:
|             EOI = 1
|     else:
|         EOI = 1             #set end of input true
| 
|     return EOI              #return the End Of Input flag value
| 
| 
| 
| if __name__ == "__main__":
|     print intro
| 
|     while not ProcessSegment(): #loop until the function returns EOI 
true
|         print "Average miles per gallon: %s" % (sumMiles / sumGallons)
|         print " "
|         
|     if sumGallons and sumMiles:
|         print "\n\nFinal average miles per gallon: %s" % (sumMiles / 
sumGallons)
|     else:
|         print "***  No data entered ***"

`----

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